Geometrical structures of different forms and with a surface subjected to contact with a material or a substance for containment, enclosure, support, transport, guides or alike of the given material or substance, which material or substance can be solids, fluids or mixtures thereof.
It is a generally know problem, that the geometrical structures need to be as little as possible damaged or influenced by the material or substance in contact with the surface of the geometrical structures.
To fulfil the primary purposes of containing, enclosure, transporting or guiding, the geometrical structures must be structurally stable and provide sufficient structural support for the material or substance to be handled or carried.
One example of accumulation of unwanted material, dirt or substances over time is known as fouling.
Another example of accumulation of unwanted material is known as scaling in which case minerals such as chalk accumulate on the structures.
As an example the case of fouling, which exist on different scales that are defined as micro and macro scale or as biofouling or inorganic fouling, the surface of a given structure tends to change over time as the fouling material tends to accumulate or to grow and thereby change the properties of the structure's interaction with the material or substance for which the structure is intended for. At either scale fouling results in numerous technical problems or loss of efficiency of the technical systems.
There are already known numerous coating compositions which provide a repellent surface. According to the book “Nanotechnology” by S. Sepeur (Vincentz Network, 2008):                A repellent surface, also called Easy-To-Clean surface, is a surface providing a low surface energy leading to hydrophobicity defined by the surface providing a static water contact angle above 90° and possibly additionally leading to oleophobicity,        Fluoropolymers and Polydimethylsiloxane are commonly used in the industry to obtain a low surface energy, with both having the disadvantage of being less scratch resistant and showing adhesion problems, and        Silane coating materials comprising silanes with perfluoroalkyl moieties have been developed to improve scratch resistance and adhesion.        
These silane based coatings comprising perfluoroalkylsilanes provide scratch and abrasion resistance with respect to visible scratches as is described U.S. Pat. No. 6,630,205, but the abrasion resistance of the coating surface's repellent properties is limited and not well documented.
US 2008/090010 A1 discloses a nanostructured hydrophobic coating suitable for reducing fouling, de-icing, comprising a monopodal silane and a low surface energy component, such as hydroxyl terminated polysiloxane. Said polysiloxane may be polydimethylsiloxane. Abrasion resistance was not investigated. The coating does not contain a polypodal silane having at least one urea or thiourethane linkage between the at least two Si atoms present in the silane molecule.
US 2003/049486 A1 discloses a coating composition comprising a monopodal silane (a vinyl silane) and polypodal silane (a bisalkoxy-silyl functional amine). The coating has anti-corrosion properties. The coating does not contain any low surface energy additive and does not contain a polypodal silane having at least one urea or thiourethane linkage between the at least two Si atoms present in the silane molecule. Addition of a low energy surface component, such as a polysiloxane to the composition is not disclosed.
WO 2009/030538 A1 discloses aqueous compositions comprising condensation products of monopodal silanes, such as basic aminosilanes and a polypodalsilane such as bis-alkoxysilyl functional amines Specific embodiments provide repellent hydrophobic surfaces by comprising perflouralkysilanes as low surface energy additive. The coating does not contain polydimethylsiloxane as surface energy additive and does not contain a polypodal silane having at least one urea or thiourethane linkage between the at least two Si atoms present in the silane molecule.
DE 102007020404 A1 disclose coatings comprising polypodal silanes in combination with a fluor containing low surface energy additive. The coatings are virtually free of monopodal silanes. The coatings do not contain a polypodal silane with at least one urea or thiourethane linkage between the at least two Si atoms present in the silane molecule. Furthermore no polydimethylsiloxane as a low-surface-energy additive is disclosed.
DE 10200450747 A1 disclose a coating comprising polypodal silanes. The coatings are virtually free of monopodal silanes. Furthermore no polydimethylsiloxane as a low-surface-energy additive is disclosed.
US 2007/017402 A1 and US 2009/0099287 A1 both discloses coating compositions or solutions containing polysiloxane, in particular polydimethylsiloxane, but with a different purpose and with mechanical and chemical properties and in particular for temperatures required for pyrolysis, e.g. in household ovens. No hydrophobic or repellent properties are mentioned. The coatings do not contain a polypodal silane having at least one urea or thiourethane linkage between the at least two Si atoms present in the silane molecule.
Thus the known coating systems still leave room for improvement, particularly with respect to the abrasion resistance and chemical resistance of the coatings' repellent surface effect.